Wednesday, 20 February 2013

Centos 6/RHEL install Krut Screen Video Capture

There are quite a few tools available for Windows users to capture the computer screen during a presentation, Camtasia, Faststone, Snagit, PicPick and others spring to mind, but Linux users are not afforded the same luxury of choice.

You can use ffmpeg on the command line for both capture and conversion and there are a few sites around with tips on this, but it can get a little difficult and messy if you haven't got the correct audio and video codecs installed, or you have not yet attained uber-geek status.

Sometimes you just want something quick and reliable which gets the job done with a minimum of fuss and this is where Krut proves itself to be a pretty capable program.

Krut is an immeasurably useful, free little tool for capturing screencasts and converting to mov video files as a standard format, after which they can be reconverted with a tool such as AviDeMux or Transcoder, which use GTK+ and FFmpeg.

Although it records audio, this is not its primary forte, which in my opinion is as a presentation screen capture tool and I would imagine that many users would record the video first then overdub the audio commentary afterwards, blending the two files. This is a simple task and as I emphasize below, you would probably achieve much better audio quality this way.

Krut has an intuitive and compact interface and boasts the following features
  • Timer-controlled recording
  • Moveable recording areas during recording
  • Preview of ongoing recording
  • Optional mouse pointer recording
  • Record/Playback at 2 different frame rates
  • Highly accurate audio-video synchronization
As it is written in Java and is available as a runnable jar file, it is very easy to use on your Centos 6/RHEL box.

Make sure you have Java installed first as you need it to run Krut, if not just follow the quick tutorial here. When installing Sun Java you might as well use the JDK (Java Development Kit) as opposed to the JRE (Java Runtime Environment), it is just as easy to install and you might need it for additional projects which may follow at a later date.

Now, to use Krut on Centos 6/RHEL, simply download the jar file from the Krut website.

Click on the download link for Linux which although marked for Ubuntu is simply a jar file (among others) which will run fine on any Linux box.

Just unzip it to your home folder and rename it 'Krut' for brevity, then cd into the Krut folder.

$ cd Krut                        now run the .jar file

$ java -jar Krut.jar             which opens the dialogue box

You will need to make adjustments, probably in screen size, which I changed to 1024x768. There are other parameters which you can play around with but changing the screen size to suit your resolution is the primary concern.

Close the settings box when done and you will be left with just the record dialogue box to start your recording. Obviously you will also need to set up whatever device or medium you are recording , then you are set to go. You will probably hit the record button first , then switch to your device or medium, editing out unwanted frames on mix-down. When finished press the stop button and wait for Krut to encode the file, which it will place in the same folder as the main Krut jar file.The file is quite a large mov, but it is simple to edit and re compress it to a smaller size, probably in H264 or Xvid/DivX. Below is my screencast recording of a small program running which I borrowed from a University course schedule, compressed to Xvid from the original mov, which reduced it from 60Mb to around 600 bytes.


I didn't add any audio but it is easy enough to overdub, in fact I would recommend always doing the audio separately on any presentation as you can tweak and mix it for maximum timbre and quality.

Audio can also be recorded and mixed on a completely different device and saved to an mp3 file, then dubbed in with the above mentioned video editing programs.

Krut can make a useful and easy addition to your Centos 6/RHEL desktop and provides an effective method for quick video screen capture and presentation.

Sunday, 3 February 2013

Centos 6/RHEL install AndroidSDK (Existing Eclipse)

If you are using an existing Eclipse installation and intend working with Android then the new ADT Bundle which comes with Eclipse attached to it is superfluous. The standalone version offers a little more control over what gets added to it. If this is the case then you will just need the Android SDK as originally supplied. Using this with an existing Eclipse installation is a fairly straightforward procedure, see the quick guide below.

First make sure you have the Sun JDK and Eclipse installed and then proceed to download the Android SDK. DO NOT get the bundle, go further down the page to 'use an existing ide' and open up the accordian to get to the download link for the SDK-Tools for Linux.

Once downloaded open a terminal and use root

$ sudo su

# cd /usr/local

# tar xvf /home/<user_name>/<android-sdk-file.tgz

This should give you an android-sdk-linux folder in /usr/local.

# chmod 755 android-sdk-linux                set permissions

Now open up Eclipse and go to Window > Preferences > Android

Browse to the android-sdk-linux installation path to set it in Eclipse. Click Apply and OK.

Now go to the Help menu and click Install New Software.

In the 'Work with' drop down list enter the following URL and put 'Android' in the title box.

This is to facilitate the installation of any extra packages which you may require in future. Check the remaining boxes.

You will need to run the SDK manager and install Platform Tools to complete the initial setup.

This process is prone to errors but it gets there in the end.

Once the platform tools has been successfully installed then you will need to select one or more platform versions to work with.

If you have added the path as above then just run

$ android                          

To view the dialogue box, or click on the icon in Eclipse.

Add your desired platform versions to continue.